Very hard to get this unless you know exactly where to shoot cos your always moving theyre always moving its a nightmare ive tried about 20 times,and yes i do have the game i pre-ordered from amazon and mostly get my games a day early :)

Kill the first three that are closest to you (one's to the left of you, one's on the right, and the third is in the stairway). If you can do that before you fall to the floor you shouldn't have a problem with the last two when you are lifted up again, which are on the left and the right of the stairs.

You don't have to reload. I got it on Veteran. Even without head shots it took 2-3 bullets per enemy. Just make sure you reload before entering the room that starts the zero-g sequence.

Very easy to get. Before you enter the door you will see a person at the stairs, shot to kill and one behind the stairs, shot to kill. Kill both before you enter the room then shoot the remaining three.... This way makes it very easy

I really loved this achievement. Such a fun one to get... not super hard. It is all about timing and definately like others have said... don't reload. I went in using my Machine gun to get rid of the first 3 plus wounding the man in the stairs... and switched to the pistol before the 2nd bump... then finished him and the guy on the left with the pistol. :)

Got it on my third try. Very simple. Before going into that room, make sure you grab an AK from one of the dead guys. Then when you walk and everything goes crazy, just aim and kill each guy and do it quick before you can thrown all around. It's not that hard whatsoever. Kill all the guys in the room before fully getting back on the ground and the achievement is yours! Very simple!

no one cares if you did it on first try props to all that actually help and give advice for the achievements and the people that admit it took them a couple of tries rather then bragging about it no one thinks your cool or good when your bragging about beating easy--medium achievement like this

Yeah, it seems weird that they would make this the secret achievement. It seems kind of trivial. Anyway, for those asking, it IS possible to unlock this achievement on "Recruit" and it's easiest to start off with the AK47u and switch to the pistol if you empty your clip. I've written more details here:

@#3 try resi5 solo then tell us its hard, also the trick is firing from the hip: 1) attain the ak-74u 2) reload and us either the 74-u or the pistol (i used pistol for the first lot) 3) rush into the next room and wait for the pilot to control things (basically when u reach the zero-g sequence) 4) dont use quick-scope, fire frow the hip and aim at the enemy 5) you shuldve killd the 3 then in the second bit finish ur clip and change to ur secondry instead of reloading i dont want feedback if you fail retry.... good luck

I missed this on my first playthrough on veteran because I didn't know it was an achievement but I went back on recruit and nailed this on my first try with the AK-74u AND I reloaded during the sequence. Very easy if you just use small bursts.